The Section on Molecular Regulation investigates how bacterial growth at the molecular level is altered so as to survive changes in nutrient availability and stress. Complex networks coordinate global patterns of gene expression with pathway-specific regulation. We focus on the role of (p)ppGpp, two simple nucleotide analogs of GTP and GDP whose only known function is regulation. Increased (p)ppGpp in E. coli can be provoked by starving for amino acids or for sources of carbon, phosphate, nitrogen or energy. The most widely studied regulatory effects of (p)ppGpp occur at the level of transcription to regulate abundance of translational machinery. Recent studies with (p)ppGpp-deficient mutants and with RNA polymerase mutants unable to bind (p)ppGpp provide rigorous opportunities to now study (p)ppGpp regulation of metabolism and protein catalysis. Interactions of (p)ppGpp with RNA polymerase have also recently been implicated in protective effects on transcription-dependent DNA repair of mutagenic lesions, which contribute to preserve genomic integrity. We continue to have an interest in sorting out how different nutritional and physical stresses are sensed and transmitted to one or the other of the two redundant enzymatic sources of (p)ppGpp synthetase in E. coli. We prefer to identify a phenomenon first with an approach that emphasizes genetics, then to pursue its understanding as needed by methods that can involve biochemistry, gene profiling or high throughput sequencing.